Is 3 minutes slow for a cistern to fill?

Hi all,

I've just installed 2 new Fluidmaster 400UK bottom entry fill valves. One of them is the brass shank model (better?) in the upstairs loo and takes 3 minutes (!) to fill the cistern. The other is the 400UK073 plastic shank, downstairs loo (more pressure above it?) and takes 2 minutes to refill.

I'm timing from the point the flush valve washer goes thunk after a flush. The downstairs loo has a brand new Fluidmaster flush valve as well so no water is leaking around the flush valve's washer and into the pan initially, as far as I can tell.

These fill valves are sold as "fast refill" so I wondered what anyone else's expectations would be or experience of these valves? They just seem to give a trickle flow. I read somewhere that 60-90 seconds is a reasonable cistern refill time. 3 minutes is way above that. 2 minutes is better but still feels slow.

There is a cold water header tank in the loft with 22mm pipe feed down to the bathroom upstairs with 15mm down to the bathroom below. There is no flexi connector on the upstairs loo so it's not like that could be restricting flow (it's 15mm copper straight onto the brass shank). I found that a 22mm gate valve was stuck in the half-closed position so replaced that but this made no difference ... still 3 minutes upstairs and 2 minutes downstairs. I've checked all the pipework has a gradient so no air locks can be restricting flow.

I've followed instructions on both valves and undone the cap, run water through to clear any debris.

What should a "fast refill" time be for these valves?

Thanks!

I think these valves are really designed for high pressure - which is ideally what your bathroom should be.
My own fills in less than a minute, 3.5 bar mains. (It's started singing like hell too )
You haven't left the pressure restrictor in the valve stem, have you?
John

Bear with me there is an ultra low pressure fitting for this valves that will speed it up. Will get part number for you shortly

http://www.mytub.co.uk/fluidmaster-low-pressure-replacemnt-seal-product-504782


Also check that any isolator valves that may be hidden are full bore.

I'm glad I asked - it's been driving me crazy. Great to know they can fill quicker.

Pressure restrictor - good call. I've also installed the 747UK073 side inlet valve (white and blue) on the tank in the roof and this had the pressure restrictor (plastic insert) which I removed (it's clear in the instructions). But these 400UK bottom entry ones make no mention of the pressure restrictor in the manual. Are you sure it has one then? If so, result!

The box for the 400UK073 (plastic shank installed downstairs) says: "New Improved High and Low Pressure Performance". So it "should" be ok in my setup?

That's a combination fill valve, should work well with either high or low pressure inlets. The issue you have is that it seems to be that they are both tank fed.
The grd floor bathroom fills a minute quicker because the vertical distance from the tank is greater therefore it has more head of pressure (I'd guess approx twice the amount) than the 1st floor bathroom.

I wouldn't expect the valve seal/diaphram to be at fault if they are brand new. Also, wouldn't expect it to fill quicker with a low pressure insert, without increasing pressure/flow.
An isolation valve may be turned down tho, always worth a check.

Its fine for your set-up. good valves to repair. more

Thanks scoobydo123 for low pressure seal link and isolator valves and Madrab too, and all.

Had a closer look and the 15mm comes off the 22mm feed, through an isolator then tees to the sink and off to the cistern through another isolator. So there are 2 isolators in the path to the cistern! I doubt they are full bore as the outside diameter looks about the same as the 15mm pipe.

So ... just before I go to Toolstation for the umpteenth time ... next step is to replace the isolators with full bore? Has this a good chance of working? Any bets on what the 3 mins will come down to? The downstairs cistern also has an isolator which I doubt is full bore too so will also replace that.

Out of interest - are bathroom cold taps supposed to be fed from mains pressure as well, or do you just mean the cistern, Burnerman. I thought hot and cold taps were all supposed to be via header tank in loft so they have a balanced pressure at sinks for mixer taps etc. And also so you don't get quick temperature changes at sink or shower when someone turns on another mains tap in the house. That's why I thought only the kitchen cold tap should be mains and all others should be via header tank. (Unless you have megaflow or similar closed system of course).

I would be looking to change the ballofix to full bore ballofix for those points where it is in-line with the cistern. The ultra low presuure diaphrams definately make a vast improvement, I had an issues in a house that was rented out, change to one of the low pressure ones and it filled much quicker.

In regards to cold taps in ideal world mains fed but can be tank fed as long as the tank in loft is approved for that purpose.

You hit the nail on the head as far as balanced hot and cold water, when it comes to mixer taps MDO. Feeding all the cold taps with the cold mains can produce exactly the behaivour you describe, if the mains flow or pressure isn't adequate and the hot is tank fed.

Will full bore valve alter the fill time, probably.... by much ... hmmm.

You could feed the toilet from the mains though if a faster fill is really what you're after.